All earthquakes
1.8
very light
EARTHQUAKE DETAILS

M1.8 earthquake · 22 km West of Ricadi (VV)

5 years ago · 27 May 2021, 09:55

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 82% of Italian events in the past year

Where

22 km West of RicadiEarthquakes in the province of Vibo ValentiaEarthquakes in Calabria

How far away could it be felt?

A quake this small is usually not felt by people: only seismographs record it.

Statistical estimate from the Italian intensity attenuation model (INGV): actual perception depends on geology, buildings and depth. Very shallow events can be felt locally even below the threshold.

Earthquake map

16 events
Magnitude:lightweakmoderatestrong

The energy released

How much energy this quake unleashed, translated into everyday comparisons.

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 its energy
M1this quakeM3

Each extra magnitude unit releases about 32 times more energy: an M5 is not "a bit stronger" than an M4 — it is a different league.

Energy estimated with the standard Gutenberg–Richter relation; an average lightning bolt ≈ 1 billion joules. Indicative values.

The race of the seismic waves

Two waves set off from the hypocentre: the faster P wave arrives first with a sharp jolt; the S wave carries the actual shaking.

P waves — the first sharp jolt (~6 km/s)S waves — the strongest shaking (~3.5 km/s)
t ≈ 26 s

Animation sped up ~5× compared to reality.

  • Messina
    48 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Reggio di Calabria
    58 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Lamezia Terme
    70 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Catanzaro
    91 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s

Theoretical times with average crustal speeds: real values vary with geology. The gap between P and S waves is what earthquake early-warning systems rely on.

How deep it was born

8 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

shallower than the area average (~86 km)

For the same magnitude, a shallow earthquake is felt much more than a deep one: the energy starts closer to the surface.

What kind of quake is this?

Aftershock

It is an aftershock: it follows a stronger quake (M3.2, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.2
The mainshock
12 km North of Tropea
5 years ago · 11 May 2021, 04:03
Activity in the area right now (30 km radius)
1
last 24 hours
3
last 7 days
15
last 30 days
10 before5 after
this quake
Strongest of the sequence3.2

How often does it happen here?

about every ~2 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 1722 events in the last 12 years of the INGV catalogue.

An average computed on the recent past: it tells how used this area is to shaking, not when the next quake will come — earthquakes cannot be predicted.

The great earthquakes in this area's history

Almost a thousand years of catalogues: the strongest documented events within ~50 km.

17837.1
Calabria meridionale earthquake
5 February 1783 · 48 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 40 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18946.1
Calabria meridionale earthquake
16 November 1894 · 43 km from here
IXDestructive: many buildings partly or fully collapse.
19285.9
Calabria centro-meridionale earthquake
7 March 1928 · 30 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Bagnara-Bovalino

The epicentre lies about 26 km from Bagnara-Bovalino, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 3 and 12 km deep

Faults are mapped to build better and understand the territory: knowing them says nothing about when an earthquake will occur, which remains unpredictable. Source: DISS 3.3 (INGV, CC BY 4.0).

Other quakes in the area

3.1
14 km West of Ricadi
13 km North-East · 170 km
5 years ago
24 May 2021, 07:09
2.2
Tirreno Meridionale [Mare]
12 km South-West · 141 km
5 years ago
5 Jun 2021, 11:20
2.4
18 km North of Villafranca Tirrena
29 km South-West · 130 km
5 years ago
6 Jun 2021, 09:29
2.2
Tirreno Meridionale [Mare]
21 km South-West · 131 km
5 years ago
15 May 2021, 03:06
2.1
5 years ago
15 May 2021, 03:03
2.4
Tirreno Meridionale [Mare]
10 km West · 159 km
5 years ago
11 May 2021, 20:16
1.6
Tirreno Meridionale [Mare]
8 km West · 150 km
5 years ago
12 Jun 2021, 05:40
2.0
Tirreno Meridionale [Mare]
21 km South-West · 143 km
5 years ago
11 May 2021, 06:11
1.8
Tirreno Meridionale [Mare]
19 km South-West · 71 km
5 years ago
12 Jun 2021, 15:05
3.2
12 km North of Tropea
29 km North-East · 52 km
5 years ago
11 May 2021, 04:03

Data: INGV — National Institute of Geophysics and Volcanology (CC-BY 4.0)

Estimates computed by Meteare on INGV data (Gutenberg–Richter relation; Italian macroseismic intensity attenuation model).